
% 在线编译网址：https://www.overleaf.com/login

\documentclass{article}
% 文章类型文档声明
\usepackage{tikz}
\usetikzlibrary{positioning, calc, shapes.geometric, shapes, shapes.multipart, arrows.meta, arrows, decorations.markings, external, trees}
% 导入主要所需宏包

\begin{document}
% 开始文档内容书写

\tikzstyle{Arrow} = [
thick, 
decoration={
	markings,
	mark=at position 1 with {
	\arrow[thick]{latex}
	}
}, 
shorten >= 3pt, preaction = {decorate}
					]
% 设置箭头格式类型

\begin{tikzpicture}
\node  (2) {L};
\node [right =of 2] (3) {A};
\node [right =of 3] (4) {Y};

\draw[Arrow] (2.east) -- (3.west);
\draw[Arrow] (2) to [out=25, in=160] (4); 
\end{tikzpicture}
% 正式画图

\end{document}